补充前端交互状态机文档和Esc测试

- 新增前端交互状态机文档，梳理全局状态、工作区工具、语义分类树、键盘快捷键、范围选择、AI页、模板确认和导入导出交互。

- 明确记录 Esc 行为：只取消当前 mask 选区和临时绘制状态，不删除已有 mask，也不清空 active class。

- 补充 CanvasArea 测试，覆盖 Esc 取消选中 mask 但保留 mask/active class，以及 Esc 取消进行中的多边形绘制。

- 更新文档索引、AGENTS 和测试计划，把前端交互状态机纳入事实文档和 R13 文档测试覆盖。

src/components/CanvasArea.test.tsx

@@ -90,6 +90,38 @@ describe('CanvasArea', () => {
     expect(maskGroup()).toHaveAttribute('data-opacity', '0.3');
   });
 
+  it('clears only the selected mask state with Escape', async () => {
+    useStore.setState({
+      activeTemplateId: '2',
+      activeClass: { id: 'c1', name: '胆囊', color: '#ff0000', zIndex: 20, maskId: 1 },
+      activeClassId: 'c1',
+      selectedMaskIds: ['m1'],
+      masks: [
+        {
+          id: 'm1',
+          frameId: 'frame-1',
+          pathData: 'M 10 10 L 80 10 L 80 80 L 10 80 Z',
+          label: '胆囊',
+          color: '#ff0000',
+          classId: 'c1',
+          segmentation: [[10, 10, 80, 10, 80, 80, 10, 80]],
+        },
+      ],
+    });
+
+    render(<CanvasArea activeTool="move" frame={frame} />);
+    fireEvent.keyDown(window, { key: 'Escape' });
+
+    await waitFor(() => expect(useStore.getState().selectedMaskIds).toEqual([]));
+    expect(useStore.getState().masks).toHaveLength(1);
+    expect(useStore.getState().masks[0]).toEqual(expect.objectContaining({
+      id: 'm1',
+      label: '胆囊',
+      color: '#ff0000',
+    }));
+    expect(useStore.getState().activeClassId).toBe('c1');
+  });
+
   it('refines one SAM2 candidate mask from an initial box with positive and negative points', async () => {
     apiMock.predictMask
       .mockResolvedValueOnce({
@@ -1817,6 +1849,21 @@ describe('CanvasArea', () => {
     expect(useStore.getState().selectedMaskIds).toEqual([useStore.getState().masks[0].id]);
   });
 
+  it('cancels in-progress polygon creation with Escape', () => {
+    render(<CanvasArea activeTool="create_polygon" frame={frame} />);
+    const stage = screen.getByTestId('konva-stage');
+    fireEvent.click(stage, { clientX: 120, clientY: 80 });
+    fireEvent.click(stage, { clientX: 220, clientY: 80 });
+
+    expect(screen.getAllByTestId('konva-circle')).toHaveLength(2);
+    fireEvent.keyDown(window, { key: 'Escape' });
+
+    expect(useStore.getState().masks).toEqual([]);
+    expect(useStore.getState().selectedMaskIds).toEqual([]);
+    expect(screen.queryAllByTestId('konva-circle')).toHaveLength(0);
+    expect(screen.getByText(/点击画布添加顶点/)).toBeInTheDocument();
+  });
+
   it('closes a clicked polygon by clicking the first node again', () => {
     render(<CanvasArea activeTool="create_polygon" frame={frame} />);
     const stage = screen.getByTestId('konva-stage');